In this week's The New Yorker, Elizabeth Kolbert writes about global warming in the first of a three-part series on climate change. The following observations are based on an online interview with Ms. Kolbert.

The principles of global warming are as well established as any in physics. Nearly a hundred and fifty years ago, a British physicist named John Tyndall discovered that certain gases in the atmosphere — we now refer to these as the "greenhouse gases" —trap heat on earth by absorbing infrared radiation. There are several naturally occurring greenhouse gases, including carbon dioxide and water vapor, and together they produce the so-called "natural greenhouse effect." Without the natural greenhouse effect, the planet would essentially be frozen. Any basic earth-science textbook talks about the natural greenhouse effect; it’s a phenomenon that is not in any way debated.

All that the theory of global warming says is that if you increase the concentration of greenhouse gases in the atmosphere, you will also increase the earth’s average temperature. It’s indisputable that we have increased greenhouse-gas concentrations in the air as a result of human activity, and it’s also indisputable that over the last few decades average global temperatures have gone up. As best as can be determined, the world is now warmer than it has been at any point in the last two millennia, and, if current trends continue, by the end of the century it will likely be hotter than at any point in the last two million years.

There is a very broad consensus in the scientific community that global warming is under way. To the extent that there are conflicting views, they are usually over how exactly the process will play out. This is understandable. The climate affects just about every natural system on earth, and these systems in turn affect the climate. So making predictions is very complicated. Meanwhile, we have only one planet, so it’s impossible to run a controlled experiment. Although the news tends to want to offer a "balanced" view by interviewing opponents of the theory along with the proponents, to focus on the degree of disagreement, rather than on the degree of consensus, is fundamentally misguided. If ten people told you your house was on fire, you would call the fire department. You wouldn’t really care whether some of them thought that the place would be incinerated in an hour and some of them thought it would take a whole day.

There is a surprisingly large, even frighteningly large, gap between the scientific community and the lay community’s opinions on global warming. Many very sober-minded, coolly analytical scientists are warning of the end of the world as we know it. There are several reasons why their message hasn’t really got out. One is that scientists tend, as a group, to interact more with each other than with the general public. Another is that there has been a very well-financed disinformation campaign designed to convince people that there is still scientific disagreement about the problem, when there really is quite broad agreement. And third, the climate operates on its own timetable. It will take several decades for the warming that is already inevitable to be felt. People tend to focus on the here and now. The problem is that, once global warming is something that most people can feel in the course of their daily lives, it will be too late to prevent much larger, potentially catastrophic changes.